In the manufacture of an electronic device, a substrate processing including plasma etching is performed to process an etching target region of a substrate. A kind of the substrate processing includes film formation and plasma etching. Such a substrate processing is described in Patent Document 1.
A substrate to which the substrate processing of Patent Document 1 is applied includes an etching target region and a mask. The mask is provided with an opening and is provided on the etching target region. The mask is a resist mask. In the substrate processing of Patent Document 1, a silicon oxide film is formed on a surface of the substrate. The silicon oxide film is formed by the film formation through atomic layer deposition. In this substrate processing, a width of the opening of the mask is adjusted by the silicon oxide film. Then, the etching target region is etched by using plasma.
Patent Document 1: Japanese Patent Laid-open Publication No. 2004-080033
As such a substrate processing including the film formation and the plasma etching, it may be considered to perform the plasma etching after forming a silicon oxide film on a surface of a substrate to protect a side surface of an opening formed in an etching target region. In this substrate processing as well as the substrate processing disclosed in Patent Document 1, an oxygen gas needs to be used to form the silicon oxide film. The oxygen gas reacts with carbon in the resist mask to cause deformation of the resist mask. Further, the oxygen gas is capable of oxidizing the etching target region. That is, the oxygen gas may inflict an undesirable damage on the substrate including the patterned region and the etching target region. Thus, in the substrate processing including the film formation and the plasma etching, it is required to suppress the damage of the substrate.
Further, in case that the etching target region is made of silicon oxide, the aforementioned silicon oxide film is removed along with the etching target region when the plasma etching is performed. Thus, if the etching target region is formed of the silicon oxide in the substrate processing including the film formation and the plasma etching, it is required to form, through the film formation, a film which can suppress, when the etching target region is plasma-etched, the etching.